Fish-aggregating devices paired with behavioral messaging produced dramatic consumption increases in Timor-Leste villages, where women were 4.17 times more likely to eat fish daily and households nearly doubled their fish purchasing (1.90x). The 2x2 factorial trial found neither fish catch technology nor social messaging alone generated significant dietary changes in these chronically malnourished communities. This dual-intervention approach addresses a persistent puzzle in nutrition science: why increasing food availability or nutrition education separately often fail to improve diets in resource-limited settings. The findings support emerging food systems thinking that simultaneous supply and demand interventions create synergistic effects absent from single-pronged approaches. For global health practitioners, this represents a template for addressing micronutrient deficiencies in isolated populations where both physical access and cultural adoption barriers exist. The magnitude of impact—over 400% increase in fish consumption among women—suggests combined interventions may overcome the behavioral inertia that undermines many nutrition programs. However, the study's geographic specificity and relatively short timeframe limit broader generalizability until replicated across diverse food-insecure contexts.